Feeding mechanism for sewing machines



March 10, 1936.. I L. BACH Ewm FEEDING MECHANISM FOR SEWING MACHINES Filed June 19, 1934 2 Sheets-Sheet 1 2.3 2l 22 74# 2L 746 g l m/ i5 LM? fLi'/ Li VI 70 72 i 3y i /30 g f f 73 I iol `2/ /7 7 2g 2 *I .12:11

Marh 9 l@ L BACH I 339ml FEEDING MEcHANIsM FOR SEWING MACHINES Filed June 19, 1954 2 Sheets-Sheet 2 lllllllllllllllLlllllmE I Y /A/n/E/VTO'R UNITED STATES PATENT OFFICE FEEDING BIECHANISM FOR SEWING MACHINES Louis Bach, Limbach, Germany Application June 19,'1934, Serial No. 731,379 In Germany March 4, 1933 6 Claims.

My invention relates to improvements in feedfeeding rollers. The object of the improvements is to provide a feeding mechanism which is simple in construction and reliable in operation, and with this object in View my invention consists in providing a mechanism for rotating the rollers, in whichin addition to the main crank pins a third or subsidiary crank pin is provided, which is out of alignment with the main crank pins, the connecting rod taking the form of a bell crank lever, or. of a'triangle.

For the purpose of explaining the invention an example embodying the same has been shown in the accompanying drawings in which the same reference characters have been used in all the views to indicate corresponding parts. In said drawings,

Fig. 1 is a sectional elevation showing the Work feeding mechanism,

Fig. 2 isa plan view of portions of Fig. 1, with parts in section,

Figs. 3 and 4 are respectively a plan view and an"elevation showing a part of the mechanism,

Figs. 5 and 6 are diagrams showing the crank mechanism and illustrating the operation thereof, and

Fig. 7 is a diagrammatic view similar to Fig. 5 showing a modified form of crank mechanism.

In the construction shown in Figs. 1 and 2 the work feeding mechanism comprises a pair of feeding rollers I and 2 which are adapted to be intermittently rotated through the intermediary of a vertical shaft 3 carrying the feeding roller I and a spur gear 4, the said spur gear being operatively connected with the main driving shaft of the machine by mechanism imparting intermittent rotary movement thereto. The spur gear 4 is in mesh with a spur gear 5 fixed to a shaft 6, and the shafts 3 and 6 are mounted in suitable bearings provided on the frame 'I of the machine. The shaft 6 projects upwardly Vbeyond the said frame, and it is formed with a reduced top part 8 providing a pivot on which an arm 9 is mounted, the said arm being located between a shoulder 8 formed on the shaft 6 and a crank disk I0 fixed to the reduced portion 8 of the shaft B.

As appears from Fig. 2, the arm 9 is angular or curved in shape, and at its free end it is formed with' an eye I2 providing a bearing for a vertical shaft I3. To the said shaft a crank disk I4 is secured which is located above the eye I2, and the disks I0 and I4 carry crank.

pins I5 and I6 which are connected by a connecting rod I8, I9. If the said crank pins were connected by an ordinary connecting rod, such as is indicated in Fig. 2 by a straight dotted line I'I, and if the crank pins I5 and I6 were on` dead centres, regular transmission of rotary movement from the crank pin I5 to the crank pin I 5 would not be possible. For this reason the connecting rod is connected with a subsidiary crank pin 2I which is out of alignment with the crank pins I5 and I6, and accordingly the connecting rod is not straight, as is indicated by the dotted line I'I, but curved or angular, and it consists of two branches I8 and I9, the subsidiary crank pin 2| engaging the connecting rod at the apex of the angle provided by the branches I8 and I9.

This curved or angular shape of both the arm` 9 and the connecting rod not only provides for the proper operation of the connecting rod with-- out the difficulty of dead center but producesV a second very beneficial result. The connecting rod and the arm 9 are thus curved away from above the feed rollers 2 and 1 so that a clear view can be had at all times of the work being. sewed. Although the height of the connecting rod and the arm 9 above the feed rollers can be adjusted as required, nevertheless it is of great advantage to have the rod curved away from the tops of the rollers so that there is a clear line of unobstructed vision directly to the point of stitching. i

The crank pin 2| is fixed to a crank disk 22 the pivot bolt 23 of which is loosely mounted in a bore of the arm 9. It will be understood that the said crank pin is not directly needed for transmitting movement from the shaft 6 to the roller 2, but it is important in so far as it enables the driven crank pin IB to pass through its dead centre, as will be explained hereinafter. l

To the bottom end of the shaft I3 a spu` gear 25 is secured which is in mesh with a spur gear 26 secured to a shaft 21 carrying the feeding roller 2. The spur gears 25 and 26 and their shafts are mounted and confined in a housing 28 which is formed with an upwardly directed sleeve 29 through which the shaft I3 is passed, the said sleeve being formed with a reduced top part 30 engaging in a corresponding socket made in the eye I2, the sleeve 29 being fixed to the eye I2 by means of a clamping screw 3I. At its bottom side the housing 28 is formed with a sleeve 32 which provides a bearing for the shaft 2'I of the feeding roller 2, and the spur gearing 26. Therefore the roller 2 is connected with the machine only through the arm 9.

The arm 9 is adapted to be rocked about the reduced end 8 of the vertical shaft 6 to which the crank disk I9 is fixed. The arm 9 is acted upon by a spring 35 so that the rollers I and 2 engage each other with a certain pressure. The said spring is embedded in a sleeve 36 secured to the frame of the machine, a screw 31 being provided for regulating the tension of the spring. With its free end the spring 35 bears on a shoulder 38 provided on the arm 9 so that the pressure of the roller 2 on the roller I depends on the tension of the spring 35.

An important feature of the construction of the machine shown in the figures is that the roller 2 is rocked away from and towards the roller I by moving in a plane, and, preferably, in a horizontal plane. Thereby the stitch forming devices are not interfered with. As is shown in Figs. 3 and 4 to the front wall 'I' of the machine casing an arm 4i] is secured, which is formed at its free end with a head 4I for the needle, a slot 42 being made in the said head for the passage of the needle. The feeding rollers I and 2 are perfectly smooth and plane on their top faces, and therefore it is not necessary to provide marginal slots in the rollers for the passage of the needle.

Therefore slight lateral movements of themargin of the roller 2 do not interfere with the formation of the seam or with the stitch forming parts.

The superior operation of my improved construction will be understood from Figs. 5 and 6.

The branches I8 and I9 of the connecting rod are rigidly connected with each other. rIhe said connecting rod preferably may be angular in form, as is shown in Figs. 2, 5 and 6, or, it may take the form of a triangle as is indicated in Fig. '7 by the line 45 representing a solid rod. In both cases the connecting rod is pivotally mounted on three crank pins I5, I 6 and 2| which always move in unison.

In Figs. 5 and 6 I have shown the said crank pins, the cranks I 0, I4 and 22 and their axes 8, I3 and 23. In Fig. 5 the said parts are shown in the positions in which the cranks I0 and I4 pass through their dead centres. If the crank I0 is the driving member, and if the third crank mechanism 2I, 22, 23 were not provided, the said driving member would not be able to move the opposite end of the connecting rod through the dead centre of the crank I4. However, by transmitting the movement through the curved or angular rod I8, I9 and the intermediate crank 22, the solid branch I8 of the connecting rod causes corresponding movement of the crank 22 when the crank I5 is rotated in clockwise direction, as is indicated in Fig. 5 by arrows, because the crank 22 is not in its dead centre relatively to the crank III, and therefore the intermediate crank 22 carries along the crank I4 by means of the branch I9 of the connecting rod, which branch is rigidly connected with the branch I8. Therefore the operation is the same as if all the crank pins I5, I6 and 2| were connected with one another by a triangle I8, I9, and 45 as shown in Fig. 7.

In Fig. 6 I have shown the parts in the positions in which the cranks I4 and 22 are relatively to each other in their dead centres. It will again be understood that the movement is not interfered with by the said cranks being in their dead centres, because with the crank I0 rotating in clockwise direction the other cranks are carried along by reason of the solid angular rod I8, I9.

From the foregoing description of the invention it will be understood that the driving mechanism of the machine is made simple in construction, by jointing the connecting rod to three cranks located out of alignment with one another. Further, the operation of the machine is simple, because the transmitting devices may be provided at one part only of the machine where they do not interfere with sewing. By mounting the outer feeding roller 2 so that the said feeding roller and the mounting thereof may be rocked away from the roller I a cardan joint may be dispensed with. The rockable arm 9 and the connecting rod carried thereby may be disposed at any suitable height, so that the said parts do not hinder the attendant guiding the fabric or attending to other work. Further, the parts may have any desired shape. As appears from Fig. 2 the intermediate crank 2I may be located any suitable distance away from the line I'I, and accordingly the arm 9 and the connecting rod I8, I9 may extend laterally as far as is desired for providing free room at the stitch forming part of the machine. However, it is not absolutely necessary to mount the mechanism for driving the outer roller 2 at a, definite height or above the said roller, and the said power transmitting mechanism may also be disposed below the plane of the rollers I and 2 and at any desired depth.

In the drawings only those parts have been shown which are necessary for explaining the invention and all the other parts have been omitted in order to give a clear understanding of the essential parts.

I claim:

1. In a driving mechanism for sewing machines, the combination, with a pair of feeding rollers, of a driving shaft in driving engagement with one of said rollers, an arm rockingly mounted on said driving shaft and having the other roller mounted thereon, a spring acting on said arm for pressing the roller mounted thereon into engagement with the first-named roller, and crank mechanism connecting said driving shaft and the roller mounted on said arm.

2. In a driving mechanism for sewing machines as claimed in claim 1, in which the crank mechanism comprises a connecting rod and three cranks engaging the said connecting rod and located out of alignment with one another.

3. In a driving mechanism for sewing machines as claimed in claim l, comprising in ad dition stitch forming mechanism having a needle guide mounted independently of the roller carried by said arm on a bracket secured to the machine casing.

4. In a driving mechanism for sewing machines, the combination, with the feeding rollers, of a driving shaft intermittently rotated in one direction connected with one of said rollers, and mechanism connecting the driving shaft with the other roller, said mechanism including three cranks having their axes parallel, the axis of one crank being located laterally with respect to the plane containing the other two axes, and a single link in the general shape of a bell crank lever connecting said cranks.

5. In a driving mechanism for sewing machnes as claimed in claim 1, a housing depending from said arm, a bearing for the roller carried by said housing and gearing connecting said roller and said crank mechanism and being mounted in said housing.

6. In a driving mechanism for sewing machines, the combination with a pair of cooperating feeding rollers on substantially vertical axes,

of a driving shaft intermittently rotated in one 10 direction connected with one of said rollers to 

